Coronary Circulation and Temp

Question 1

Which usually supplies the posterior part of the heart, the RCA or LCA?

Answer 1

RCA

Question 2

What is the arterial plexus that connects the epicardial coronary arteries to the subendocardial arterial plexus?

Answer 2

Myocardial cessel network

Question 3

Which part of the coronary arteries is most susceptible to compression during systole?

Answer 3

The subendocardial arterial plexus

Question 4

What general division of the coronary arteries are the most frequent site of MIs?

Answer 4

The subendocardial arterial plexus

Question 5

What is Ohm’s law?

Answer 5

Flow = ΔP/R

Question 6

Is ΔP between the coronary arteries and the aorta small or large during ventricular diastole?

Answer 6

Large

Question 7

Is ΔP between the coronary arteries and the aorta small or large during ventricular systole? What causes this?

Answer 7

Small

caused by increase in coronary artery pressur

Question 8

Is ΔP between the coronary arteries and the aorta small or large during ventricular ejection?

Answer 8

Small, but nonzero

Question 9

The LV is maximally perfused during which part of the cardiac cycle?

Answer 9

Diastole

Question 10

When is the ΔP between the aortic pressure and the at a minimum?

Answer 10

At the end of isovolumic contraction

Question 11

The magnitude of ΔP is small or larger in the right ventricle compared to the left? What is the consequence of this?

Answer 11

Smaller, meaning that the right ventricle is better perfused

Question 12

Which point on the cardiac cycle graph corresponds to the lowest level of flow?

Answer 12

The upper right, at the end of isovolumic contraction

Question 13

What is the equation for tension on the walls of the heart?

Answer 13

T = Pressure x Radius

Question 14

What happens in dilated cardiomyopathy to wall tension?

Answer 14

Increases at every pressure (d/t increased radius)

Question 15

What is the equation for the resistance, relative to the radius?

Answer 15

R = r^-4

Question 16

What is Poiseuille’s law?

Answer 16

R=8ℓƞ/πr4

Question 17

What specific metabolite that increases in the heart due to increased work causes vasodilation?

Answer 17

Adenosine (from turnover of ATP)

Question 18

What is the adrenergic receptor in the heart? What is the neurotransmitter that this responds to? What is the effect?

Answer 18

Beta 1
Norepi
Increaes HR

Question 19

What are the two receptors in the coronary arteries that cause vasoconstriction and vasodilation?

Answer 19

Alpha 1 = vasoconstriction
Beta 1 = vasodilation

(***from book)

Question 20

Core temperature is regulated within what range?

Answer 20

_+1 degree F

Question 21

How does core temperature change throughout the day?

Answer 21

Rises from waking, until late evening when it falls

Question 22

The luteal phase of the estrous cycle in denoted by what change in temperature (increase or decrease)?

Answer 22

Increase

Question 23

What is the way that the body can increase heat production?

Answer 23

Metabolism (shivering is also an acceptable answer)

Question 24

What are the four mechanisms of heat transfer that the body uses?

Answer 24

1. Radiation
2. Conduction
3. Convection
4. Evaporation

Question 25

What is radiation?

Answer 25

Infrared heat rays moving down a gradient

Question 26

Which type of colors reflect radiated heat wave (light or dark?)

Answer 26

Light

Question 27

What is conduction?

Answer 27

Movement of heat through physical touching of the two objects

Question 28

What is conductivity? What is air's conductivity relative to water?

Answer 28

The rate at which heat can be transferred Air is very low relative to water

Question 29

Vasodilation utilizes which mechanism of heat transfer to rid the body of excess heat?

Answer 29

Conduction

Question 30

Vasoconstriction utilizes which mechanism of heat transfer to maintain heat?

Answer 30

Conduction

Question 31

What is convection?

Answer 31

Transfer of heat by using an intermediate (e.g. heating air to heat a cake)

Question 32

Is the transfer of heat via convection more efficient in air or water?

Answer 32

Water

Question 33

Is there any mechanism of heat transfer that does not move down its concentration gradient? If so, which one?

Answer 33

None

Question 34

What is the receptor and neurotransmitter that innervated sweat glands?

Answer 34

sympathetic fibers, utilizing ACh

Question 35

What is the effect of humidity on the rate of evaporation?

Answer 35

lowers it

Question 36

What is the heat sensing center of the brain?

Answer 36

Anterior hypothalamic-preoptic area

Question 37

Do we have more cold or heat receptors on our skin? What about on our anterior hypothalamus?

Answer 37

More cold than heat on skin. The reverse is true for the hypothalamus

Question 38

Where are the three cold/heat receptors located in the core of our bodies (not including skin)?

Answer 38

Spinal cord Abdominal cavity Great veins

Question 39

What is the role of ther posterior hypothalmus in temperature control?

Answer 39

Relay station for sensory inputs from periphery and anterior hypothalamus Integrates response to warm or cool body

Question 40

What happens to the rate of heat/cold receptor discharge if the stimulus is maintained?

Answer 40

Sensitization

Question 41

How is vasodilation of the skin effected?

Answer 41

ANS withdrawal

Question 42

How do infants maintain body temp if they cannot shiver?

Answer 42

Uncoupling of oxidative phosphorylation in brownt fat

Question 43

Where is the shivering signal generated from?

Answer 43

Posterior hypothalamus

Question 44

What is the long term strategy to adapt to cold conditions?

Answer 44

Thyroxine secretion

Question 45

How does thyroxine secretion lead to a long term increase in BMR? (3)

Answer 45

1. Increases thyrotropin releasing hormone 2. Increases TSH 3. Increases Thyroxine

Question 46

What happens to the set point of shivering with increases in skin temperature?

Answer 46

Decreases

Question 47

Can angina increase with hot or cold temps?

Answer 47

Cold

Question 48

How can heat increase HR?

Answer 48

accelerate slope of the pacemaker potential